The present invention evolved from continuing development efforts pertaining to subject matter disclosed in my co-pending Application Ser. No. 216,872, filed Dec. 15, 1980 entitled "Balun Coupled Microwave Frequency Converter" now issued as U.S. Pat. No. 4,330,868, on May 18, 1982. This patent discloses a diode mixer bridge with a balanced port and an unbalanced port.
The present invention relates to improvements in the microstrip circuit layout and structure for the balanced port. The invention enables a wider coupling gap between the balanced conductors providing the balanced port for the diode mixer bridge. This wider coupling gap is easier to implement and reduces manufacturing cost. The invention has widespread application to various types of mixers having a balanced port.